Rotary engine



(No Model.)

P. B.. MERRILL. ROTARY ENGINE.

Patented Jan. 2

Z km uns. l E u NITED STATES ATENT Erice.

FREDERICK BURDETTE MERRILL, OF CHICAGO, ILLINOIS.

ROTARY' ENGIN E.

SPECIFICATION forming part of Letters Patent No. 511,964, dated January2, 1894.

Application tiled October 8, 1892. Serial No. 448,240. (No model.)

To @ZZ whom it may concern: Be it known that I, FREDERICK BURDETTMERRILL, a citizen of the United States, residing at Chicago, in thecounty of Cook and State of Illinois, have invented certain new anduseful Improvements in Rotary Engines, of which the following is a full,clear, and exact description, that will enable others to make and usethe same, reference being had to the accompanying drawings,formingapartof this specification.

This invention relates to improvements in rotary engines, and has forits object to pro-y vide an engine of this character wherein the streamis used expansively so as to obtain the best possible results with theleast expenditure of fuel.

Figure l is a longitudinal section and elevation of the cylinder andpiston; Fig. 2, an end elevation; and Fig. 3, a transverse sectionlooking in the direction indicated bythe arrow.

The rotary piston is of such a construction that the steam is retainedin the cylinder for some considerable length of time, so that nearlythefull power of the same is expended before it finally reaches theexhaust-ports.

In the drawings, A is the cylinder, B the piston, C the shaft upon whichthe piston is mounted, and D D the cap ends bolted to and closing therespective ends of the cylinder.

In the illustration, the longitudinal dimensions of the piston andcylinder are proportionately much greater with reference to the diameterof the same than is ordinarily the case in this class of engines. Theproportional dimensions will be varied, however, as practical use andcircumstances may require without in any Way departing from the spiritof my invention. This rotary piston is provided with, on its peripheralsurface, a series of continuous spiral grooves, a ai, starting in from acentral point and running or extending in the direction of each end, asshown.

In the bottom of the continuous spiral grooves, a d, are arranged, atintervals, a number of buckets,- a', which are acted upon by the steamin imparting the required rotary motion to' the piston; the action beingsimilar to that of the ordinary water-wheel. The iirst series of spiralsteam grooves, a a, terminates in the cored passages, d2 0,2,in thesolid part as of the piston and through which the volume of steamescapes into the second 5 5 series of spiral grooves, b b, whichcontinues nearly to the respective ends of the piston; the steam finallyescaping into the exhaustports h b. The second series of grooves issomewhat wider than the first series so that 6o the escaping volume ofsteam may have more room to expand as it nears the exhaust-ports andthus avoid any undue back pressure. The second series of spiral grooves,b l), 1s

also provided with steam vanes or buckets.

It is obvious that the spiral grooves or chambers may be in onecontinuous series instead of being divided into two series connected bya passage, as shown. The spiral grooves may also start in at one end andter- 7o minate at the other; the steam-supply and exhaust-portsoccupying the same relative po sitions.

E is the steam-supply pipe, and CZ the steamport in the cylinder.

The arrangement of taking steam at the longitudinal center of thecylinder and having the spiral grooves in the piston extend in the rightand left order shown, is preferred as the pressure is more equallydistributed 8o and a more uniform action secured. B v this constructionthe steam is retained in the cylinder for a longer period than isordinarily the case, and has a continuous impact on the brackets in thespiral grooves until the exhaust f ports are reached. The respectiveends of the cylinder are provided with stuffing-boxes g g, for thepiston-shaft extending therethrough.

Having thus described my invention, what 9o I claim as new, and desireto secu re by Letters Patent, is

In a rotarysteam engine, the cylinder having a uniform internaldiameter, central inlet port, and an exhaust port near each end,the

rotary piston within said cylinder having a series of spiral groovesstarting near the middle and extending toward each end of the piston,saidA grooves being of greater sectional area as they approach the endsof the pisim ton, the grooves being provided With steam vanes orbuckets, and the piston with a suitable shaft, ail being combined andrelatively arranged substantially as described.

FREDERICK BURDETTE MERRILL. Vitnesses:

L. M. FREEMAN, L. B. COUPLAND.

